Chapter 12 - Musculoskeletal System: BONES Flashcards
What makes up the Axial Skeleton (80 Bones)
The axial skeleton supports the head, neck, back, and chest and thus forms the vertical axis of the body.
It consists of the skull, vertebral column; the sacrum, coccyx, The thoracic cage; ribs and sternum.
What makes up the appendicular skeleton ( 126)
It is joined by a multitude of joints, ligaments, and cartilage, form the appendicular skeleton.
This allows for greater motion and movement when compared to the axial skeleton.
The appendicular skeleton bones are vital for movement, locomotion, and overall function of the human body
- Shoulder Girdle; Clavicle, Scapula
- Upper Limbs; Humerus, Radius, Ulna, Carpals, Metacarpals, Phalanges
- Lower Girdle; Femur, Tibia, Fibula, Tarsals,Metatarsals, Phalanges, Calcaneus (heel) - Subtalar Joint
- Pelvic Girdle; The coxal bone (hip bone, pelvic bone) is a large, flattened, irregularly shaped bone, constricted in the center and expanded above and below.
Pelvis, Pubis Symphysis
How many bones in body - where
When Born = 270 - 300 bones
At 25 bones completely fuse into larger bones = 206 bones
Axial Skeleton = 80 bones
- Skull 29
- Vertebral Column 26
- Thorax 25
- Ossicles 6
Appendicular Skeleton = 126 Bones
- Shoulder Girdle 4
- upper limb 60
- pelvic girdle 2
- lower limb 60
What are the main functions of the bone?
- Frame and support; provides a firm framework that gives shape and support to the body parts.
- prevents soft tissue from collapsing in a heap
- provides points of attachment for most muscles in the body - Movement; bones act as an anchor for muscles to attach to so that the body can move.
- Protection of Vital organs; bone making up Skelton is hard structures encasing vital organs so that bones receive the main force/harm first before organs, spinal chord ect.
- Storage organs; for minerals (salts) and fats
Minerals stored; K, Na, Ca, P
These can be distributed to other regions of the circulatory system when required Eg. Preggo has no Ca, it can be removed from skeleton bones for foetus growth - Blood cell production; Red marrow within bones has stem cells that can differentiate into blood cells. Factors in cells environment determines whether they become RBC, WBC or platelets
What is the Periosteum
The periosteum is a dense, white, fibrous membrane covering the outer surface of bone
- no periosteum at joints where bones are covered with articulations cartilage
A typical long bone consist of Diaphysis and Epiphysis, what are they?
Diaphysis - a shaft making up most the bone
Epiphysis - the ENDS; enlarged ends of the bone with a thin layer of articular cartilage
When bone is cut lengthwise, explain what is seen.
Diaphysis is seen to be hollow cylindrical COMPACT BONE surrounding the cavity.
This cavity is used as fat storage site = Yellow bone marrow cavity
Epiphysis has compact bone on the outside but the central regions contain SPONGY/ CANCELLOUS bone.
Certain bones here have RBC production RED BONE MARROW
What is bone
Bone is a connective tissue (hardest connective tissue)
- consists of cells separated from each other by larger amounts of non cellular material called a matrix
Cells + matrix = bone
A bone is rigid + strong in strength because of inorganic salts deposited in Matrix
Has brittle and calcified matrix (Calcium phosphate) with many collagen fibres, giving bones a degree of Pliability (flexibility)
3 types of cells occur in bones
What is the medullary cavity
It is the cavity found in long bones filled with yellow bone marrow ( stores fat - energy)
What are the three types of cells found in Bones
- Osteoblasts (for building bones)
- young cell that produces bone
- forms bone matrix; calcium phosphate + collagen fibres = rigid bone - Osteocytes
- bone cells formed from osteoblasts
- mature bone cells embedded or trapped in matrix
- maintains bone tissue/ matrix - Osteoclasts ( bone breaking)
- Reabsorbs (destroys) bone tissue
- makes acidic environment to dissolve bone ( makes cavities)
- active during growth or healing or ageing
What is the structure of a compact bone?
Compact bone is a very hard bone which runs vertically along the length of the long bone to provide strength
It is made up of Osteons or Haverison systems
What are Haversion systems?
Bone is Made up of round units called OSTEONS/ Haveriosn systems
- are circular layers of bone ( LAMELLAE) surrounding central HAVERSION CANAL which carries Blood, Lymph vessels and Nerves
- small spaces in Matrix are called LACUNAE, bone cell (OSTEOCYTES) occupies each lacunae
- tiny canals = canaliculi, runs between the lacunae
- cytoplasmic projections from bone cell all go into canaliculi - so adjacent cells can connect
Bone cells + Blood vessels = haverison systems/ Osteon
What is the structure of spongy bone?
- found in epiphysis region of long bone
- have no haversion systems
- TRABECULAE= irregular arrangement of thin bony parts
- osteocytes in trabeculae
- blood vessels, lymph vessels and nerves are found
- in adults= bone marrow confined to these cavities
Epipseal line of cartilage - remnant of plate seen in young growing bones.
Trabeculae + small spaces (containing bone marrow - red) + B.V
What is ossification?
Bones of the skeleton are formed from hyaline cartilage ( in embryo) by a process of ossification (bone formation) and they grow by bone remodelling.
From 8wks - birth = bony skeleton
Bone remodelling is also important in bone repair/ fractures
List the three types of cartilage
- Hyaline
- Elastic
- Fibro - cartilage